*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
    --bg: #0a0a0a;
    --bg-secondary: #111111;
    --bg-card: #1a1a1a;
    --bg-card-hover: #222222;
    --text: #f1f1f1;
    --text-secondary: #a0a0a0;
    --accent: #1d9bf0;
    --accent-hover: #1a8cd8;
    --accent-glow: rgba(29, 155, 240, 0.15);
    --gradient: linear-gradient(135deg, #1d9bf0 0%, #8b5cf6 50%, #ec4899 100%);
    --gradient-text: linear-gradient(135deg, #1d9bf0, #a78bfa);
    --border: rgba(255,255,255,0.08);
    --border-hover: rgba(255,255,255,0.15);
    --shadow: 0 4px 24px rgba(0,0,0,0.4);
    --radius: 16px;
    --radius-sm: 10px;
    --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --max-width: 1200px;
    --nav-height: 64px;
}

html { scroll-behavior: smooth; }

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
}

a { color: var(--accent); text-decoration: none; transition: color var(--transition); }
a:hover { color: var(--accent-hover); }

img { max-width: 100%; display: block; }

.container { max-width: var(--max-width); margin: 0 auto; padding: 0 24px; }

.section { padding: 100px 0; }
.section-label {
    display: inline-block;
    font-size: 0.8rem;
    font-weight: 600;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--accent);
    margin-bottom: 16px;
    padding: 6px 14px;
    border-radius: 20px;
    background: var(--accent-glow);
    border: 1px solid rgba(29, 155, 240, 0.2);
}
.section-title {
    font-size: 2.5rem;
    font-weight: 800;
    margin-bottom: 16px;
    letter-spacing: -0.02em;
    line-height: 1.2;
}
.section-desc {
    font-size: 1.1rem;
    color: var(--text-secondary);
    max-width: 600px;
    margin-bottom: 48px;
}

.gradient-text {
    background: var(--gradient-text);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* Navbar */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--nav-height);
    z-index: 1000;
    background: rgba(10,10,10,0.85);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border);
    transition: all var(--transition);
}
.navbar .container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 100%;
}
.nav-logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text);
}
.nav-logo .logo-icon {
    width: 32px;
    height: 32px;
    border-radius: 8px;
    object-fit: cover;
}
.nav-links {
    display: flex;
    align-items: center;
    gap: 32px;
    list-style: none;
}
.nav-links a {
    color: var(--text-secondary);
    font-size: 0.9rem;
    font-weight: 500;
    transition: color var(--transition);
}
.nav-links a:hover { color: var(--text); }
.nav-links a.active { color: var(--accent); }

.lang-switch {
    position: relative;
}
.lang-btn {
    display: flex;
    align-items: center;
    gap: 6px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    color: var(--text);
    padding: 8px 14px;
    border-radius: 8px;
    cursor: pointer;
    font-size: 0.85rem;
    font-family: inherit;
    transition: all var(--transition);
}
.lang-btn:hover { border-color: var(--border-hover); background: var(--bg-card-hover); }
.lang-btn .arrow { font-size: 0.6rem; transition: transform var(--transition); }
.lang-btn.open .arrow { transform: rotate(180deg); }
.lang-dropdown {
    position: absolute;
    top: calc(100% + 8px);
    right: 0;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    min-width: 180px;
    max-height: 320px;
    overflow-y: auto;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-8px);
    transition: all var(--transition);
    box-shadow: var(--shadow);
    z-index: 100;
}
.lang-dropdown.show { opacity: 1; visibility: visible; transform: translateY(0); }
.lang-dropdown button {
    display: block;
    width: 100%;
    text-align: left;
    padding: 10px 16px;
    background: none;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    font-size: 0.85rem;
    font-family: inherit;
    transition: all var(--transition);
}
.lang-dropdown button:hover { color: var(--text); background: rgba(255,255,255,0.04); }
.lang-dropdown button.active { color: var(--accent); font-weight: 600; }

.mobile-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    cursor: pointer;
    padding: 4px;
    background: none;
    border: none;
}
.mobile-toggle span {
    display: block;
    width: 22px;
    height: 2px;
    background: var(--text);
    border-radius: 2px;
    transition: all var(--transition);
}

/* Hero */
.hero {
    padding: 160px 0 100px;
    text-align: center;
    position: relative;
    overflow: hidden;
}
.hero::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(ellipse at 50% 0%, var(--accent-glow) 0%, transparent 60%);
    pointer-events: none;
}
.hero .container { position: relative; z-index: 1; }
.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 8px 18px;
    border-radius: 24px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin-bottom: 32px;
}
.hero-badge .dot { width: 8px; height: 8px; border-radius: 50%; background: #22c55e; }
.hero-title {
    font-size: 3.8rem;
    font-weight: 900;
    line-height: 1.1;
    letter-spacing: -0.03em;
    margin-bottom: 20px;
}
.hero-subtitle {
    font-size: 1.2rem;
    color: var(--text-secondary);
    max-width: 560px;
    margin: 0 auto 48px;
}
.hero-buttons {
    display: flex;
    gap: 16px;
    justify-content: center;
    flex-wrap: wrap;
}
.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 14px 28px;
    border-radius: 12px;
    font-size: 0.95rem;
    font-weight: 600;
    font-family: inherit;
    cursor: pointer;
    transition: all var(--transition);
    border: none;
}
.btn-primary {
    background: var(--accent);
    color: #fff;
}
.btn-primary:hover { background: var(--accent-hover); transform: translateY(-1px); box-shadow: 0 8px 24px rgba(29,155,240,0.3); }
.btn-secondary {
    background: var(--bg-card);
    color: var(--text);
    border: 1px solid var(--border);
}
.btn-secondary:hover { border-color: var(--border-hover); background: var(--bg-card-hover); transform: translateY(-1px); }
.btn-outline {
    background: transparent;
    color: var(--text);
    border: 1px solid var(--border);
}
.btn-outline:hover { border-color: var(--accent); color: var(--accent); }
.product-buttons {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
}
.btn-github {
    background: #24292e;
    color: #fff;
    border: 1px solid #24292e;
}
.btn-github:hover {
    background: #3a3a3a;
    border-color: #3a3a3a;
    transform: translateY(-1px);
}
.btn-github svg {
    flex-shrink: 0;
}

/* Products */
.products-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 24px;
}
.product-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 40px;
    transition: all var(--transition);
    position: relative;
    overflow: hidden;
}
.product-card:hover {
    border-color: var(--border-hover);
    background: var(--bg-card-hover);
    transform: translateY(-2px);
    box-shadow: var(--shadow);
}
.product-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    border-radius: 3px 3px 0 0;
}
.product-card.desktop::before { background: var(--gradient); }
.product-card.extension::before { background: linear-gradient(135deg, #22c55e, #1d9bf0); }
.product-icon {
    width: 56px;
    height: 56px;
    border-radius: 14px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    margin-bottom: 24px;
}
.product-card.desktop .product-icon { background: rgba(139,92,246,0.15); }
.product-card.extension .product-icon { background: rgba(34,197,94,0.15); }
.product-name {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 8px;
}
.product-badge {
    display: inline-block;
    font-size: 0.75rem;
    font-weight: 600;
    padding: 4px 10px;
    border-radius: 6px;
    margin-bottom: 16px;
}
.product-card.desktop .product-badge { background: rgba(139,92,246,0.15); color: #a78bfa; }
.product-card.extension .product-badge { background: rgba(34,197,94,0.15); color: #4ade80; }
.product-desc {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.7;
    margin-bottom: 24px;
}
.product-features {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 10px;
    margin-bottom: 28px;
}
.product-features li {
    display: flex;
    align-items: flex-start;
    gap: 10px;
    font-size: 0.9rem;
    color: var(--text-secondary);
}
.product-features li .check {
    color: #22c55e;
    flex-shrink: 0;
    margin-top: 2px;
}

/* Features */
.features-section { background: var(--bg-secondary); }
.features-tabs {
    display: flex;
    gap: 8px;
    margin-bottom: 40px;
    flex-wrap: wrap;
}
.feature-tab {
    padding: 10px 20px;
    border-radius: 10px;
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    background: transparent;
    border: 1px solid var(--border);
    color: var(--text-secondary);
    font-family: inherit;
    transition: all var(--transition);
}
.feature-tab:hover { border-color: var(--border-hover); color: var(--text); }
.feature-tab.active { background: var(--accent); border-color: var(--accent); color: #fff; }
.feature-content { display: none; }
.feature-content.active { display: block; }
.feature-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
}
.feature-item {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 28px;
    transition: all var(--transition);
}
.feature-item:hover { border-color: var(--border-hover); background: var(--bg-card-hover); }
.feature-item .feat-icon {
    width: 44px;
    height: 44px;
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    margin-bottom: 16px;
    background: var(--accent-glow);
}
.feature-item h4 { font-size: 1rem; font-weight: 600; margin-bottom: 8px; }
.feature-item p { font-size: 0.85rem; color: var(--text-secondary); line-height: 1.6; }

/* Languages */
.lang-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 12px;
}
.lang-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 16px 20px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    transition: all var(--transition);
}
.lang-item:hover { border-color: var(--border-hover); background: var(--bg-card-hover); }
.lang-flag { font-size: 1.4rem; }
.lang-name { font-size: 0.9rem; font-weight: 500; }
.lang-code { font-size: 0.75rem; color: var(--text-secondary); }

/* Install */
.install-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 24px;
}
.install-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 36px;
}
.install-card h3 {
    font-size: 1.3rem;
    font-weight: 700;
    margin-bottom: 20px;
}
.install-browser-list {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 24px;
}
.install-browser-item h4 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 12px;
    color: var(--text);
}
.install-steps {
    list-style: none;
    counter-reset: step;
}
.install-steps li {
    counter-increment: step;
    display: flex;
    align-items: flex-start;
    gap: 14px;
    margin-bottom: 16px;
    font-size: 0.9rem;
    color: var(--text-secondary);
}
.install-steps li::before {
    content: counter(step);
    flex-shrink: 0;
    width: 28px;
    height: 28px;
    border-radius: 50%;
    background: var(--accent-glow);
    color: var(--accent);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.8rem;
    font-weight: 700;
}
.install-steps li code {
    background: rgba(255,255,255,0.06);
    padding: 2px 8px;
    border-radius: 4px;
    font-size: 0.85em;
}

/* FAQ */
.faq-list { max-width: 800px; }
.faq-item {
    border-bottom: 1px solid var(--border);
    padding: 24px 0;
}
.faq-question {
    width: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
    text-align: left;
    background: none;
    border: none;
    color: var(--text);
    font-size: 1.05rem;
    font-weight: 600;
    cursor: pointer;
    font-family: inherit;
    padding: 0;
    gap: 16px;
}
.faq-question .faq-icon { font-size: 1.2rem; transition: transform var(--transition); flex-shrink: 0; }
.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s ease, padding-top 0.4s ease;
}
.faq-item.open .faq-answer { max-height: 200px; padding-top: 12px; }
.faq-item.open .faq-question .faq-icon { transform: rotate(45deg); }
.faq-answer p { color: var(--text-secondary); font-size: 0.95rem; line-height: 1.7; }

/* Stats */
.stats-section { background: var(--bg-secondary); }
.stats-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
    text-align: center;
}
.stat-item .stat-number {
    font-size: 2.5rem;
    font-weight: 900;
    background: var(--gradient-text);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}
.stat-item .stat-label { font-size: 0.9rem; color: var(--text-secondary); margin-top: 4px; }

/* Footer */
.footer {
    background: var(--bg-secondary);
    border-top: 1px solid var(--border);
    padding: 48px 0 32px;
}
.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 40px;
    margin-bottom: 40px;
}
.footer-brand .logo-icon {
    width: 36px;
    height: 36px;
    border-radius: 8px;
    object-fit: cover;
    margin-bottom: 16px;
}
.footer-brand p { font-size: 0.9rem; color: var(--text-secondary); max-width: 280px; line-height: 1.7; }
.footer-col h4 { font-size: 0.85rem; font-weight: 600; margin-bottom: 16px; text-transform: uppercase; letter-spacing: 0.06em; color: var(--text-secondary); }
.footer-col ul { list-style: none; display: flex; flex-direction: column; gap: 10px; }
.footer-col a { font-size: 0.9rem; color: var(--text-secondary); transition: color var(--transition); }
.footer-col a:hover { color: var(--text); }
.footer-bottom {
    border-top: 1px solid var(--border);
    padding-top: 24px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.85rem;
    color: var(--text-secondary);
}

/* Responsive */
@media (max-width: 968px) {
    .products-grid, .install-grid { grid-template-columns: 1fr; }
    .feature-grid { grid-template-columns: repeat(2, 1fr); }
    .lang-grid { grid-template-columns: repeat(3, 1fr); }
    .stats-grid { grid-template-columns: repeat(2, 1fr); }
    .footer-grid { grid-template-columns: 1fr 1fr; }
    .hero-title { font-size: 2.8rem; }
    .section-title { font-size: 2rem; }
}

@media (max-width: 640px) {
    .nav-links { display: none; }
    .mobile-toggle { display: flex; }
    .nav-links.mobile-open {
        display: flex;
        flex-direction: column;
        position: absolute;
        top: var(--nav-height);
        left: 0;
        right: 0;
        background: var(--bg);
        border-bottom: 1px solid var(--border);
        padding: 20px 24px;
        gap: 16px;
    }
    .feature-grid { grid-template-columns: 1fr; }
    .lang-grid { grid-template-columns: repeat(2, 1fr); }
    .hero-title { font-size: 2.2rem; }
    .section-title { font-size: 1.7rem; }
    .hero { padding: 120px 0 60px; }
    .section { padding: 60px 0; }
    .footer-grid { grid-template-columns: 1fr; }
    .footer-bottom { flex-direction: column; gap: 8px; text-align: center; }
    .install-browser-list { grid-template-columns: 1fr; }
}